Glycols, particularly aryl substituted 1,3-propanediols are valuable chemical compounds useful as intermediates for the preparation of a variety of pharmaceutical compounds.
Much attention has been directed to the preparation of these propanediols in commercial quantities. The ideal process utilizes inexpensive reactants, operates under mild conditions and obtains the desired product in high yields.
A number of processes have been disclosed for making 1,3-propanediols on a commercial scale. For example, Frank J. Stiefel, U.S. Pat. Nos. 4,868,327 and 5,072,056, disclose a method of preparing 2-phenyl-1,3-propanediol by forming a benzaldehyde oxime and oxidizing the oxime to produce nitromethylbenzene. This compound is allowed to react with formaldehyde to form 2-nitro-2-phenyl- 1,3-propanediol which is then hydrogenated in the presence of a palladium catalyst to produce the diol.
Mark A. Murphy et al., U.S. Pat. No. 4,873,378 discloses the hydrocarbonylation reaction of an epoxide using rhodium as a catalyst.
Young M. Choi, U.S. Pat. No. 4,982,016 discloses a process in which diethyl phenylmalonate is reduced with a metal hydride complex in solution with a heterocyclic ether such as tetrahydrofuran.
While some of these processes have been commercialized, the preparation of 2-aryl-1,3-propanediols remains expensive to manufacture on a commercial scale.
It would therefore be of significant benefit particularly for the production of pharmaceutical compounds from 2-aryl-1,3-propanediols to provide a process for making the diols using inexpensive starting materials under mild process conditions and the minimum process steps to obtain the desired product in high yields.